CLDC-2467 Add hint text to period question (#1780)

* add hint text

* test

app/models/form/lettings/questions/period.rb

@@ -6,7 +6,7 @@ class Form::Lettings::Questions::Period < ::Form::Question
     @header = "How often does the household pay rent and other charges?"
     @type = "radio"
     @check_answers_card_number = 0
-    @hint_text = ""
+    @hint_text = "Select how often the household is charged. This may be different to how often they pay."
     @answer_options = ANSWER_OPTIONS
     @question_number = 92
   end

config/forms/2022_2023.json

@@ -7443,7 +7443,7 @@
                 "period": {
                   "check_answer_label": "Frequency of household rent and charges",
                   "header": "How often does the household pay rent and other charges?",
-                  "hint_text": "",
+                  "hint_text": "Select how often the household is charged. This may be different to how often they pay.",
                   "type": "radio",
                   "answer_options": {
                     "2": {

spec/models/form/lettings/questions/period_spec.rb

@@ -0,0 +1,11 @@
+require "rails_helper"
+
+RSpec.describe Form::Lettings::Questions::Period, type: :model do
+  subject(:question) { described_class.new(nil, nil, page) }
+
+  let(:page) { instance_double(Form::Page) }
+
+  it "has the correct hint" do
+    expect(question.hint_text).to eq("Select how often the household is charged. This may be different to how often they pay.")
+  end
+end